<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>typeof方法</title>
</head>
<body>

</body>
<script>
    let v=undefined;
    document.write(typeof v+"<br>");
    v="true";
    document.write(typeof(v)+"<br>");
    v=1;
    document.write(typeof(v)+"<br>");
    v=NaN; //not a number  类型转换成数字失败时会显示
    document.write(typeof(v)+"<br>");
    v=true;
    document.write(typeof(v)+"<br>");
    v=null;
    document.write(typeof(v)+"<br>");
    v=10n;
    document.write(typeof(v)+"<br>");


</script>
</html>